Author(s)

H.N. Oguz & J. Zeng

Abstract

The formation of an air bubble from a hypodermic needle in a tube is in- vestigated. Results show that the presence of a flow in the tube reduces substantially the detachment size of the bubbles. This effect can be ex- plained by the added mass force that causes early detachment of the bubble from the needle. The process is highly transient and therefore suitable for boundary-integral potential-flow simulations. Some simple experiments are also carried out and seem to support the predictions obtained by the boundary integral calculations. 1 Introduction The simplest way of enhancing gas transfer to liquids is to increase the gas-liquid interfacial area by the injection of bubbles through a submerged orifice. This process is commonly used in industry and a large body of liter

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